High fidelity simulation of the mechanical behavior of closed-cell polyurethane foams

TL;DR

This paper presents a detailed finite element simulation of closed-cell polyurethane foams' mechanical behavior, accurately modeling microstructural details and validating results against experiments, leading to an analytical predictive model for foam design.

Contribution

It introduces a comprehensive microstructure-based simulation method and an analytical model to predict foam behavior, improving design for energy absorption applications.

Findings

Accurately reproduces initial stiffness, plateau stress, and hardening in foams.

Provides good estimates of energy dissipation and elastic energy storage.

Validates simulation results with experimental data.

Abstract

The mechanical behavior of closed-cell foams in compression is analyzed by means of the finite element simulation of a representative volume element of the microstructure. The digital model of the foam includes the most relevant details of the microstructure (relative density, cell size distribution and shape, fraction of mass in the struts and cell walls and strut shape), while the numerical simulation takes into account the influence of the gas pressure in the cells and of the contact between cell walls and struts during crushing. The model was validated by comparison with experimental results on isotropic and anisotropic polyurethane foams and it was able to reproduce accurately the initial stiffness, the plateau stress and the hardening region until full densification in isotropic and anisotropic foams. Moreover, it also provided good estimations of the energy dissipated and of the elastic energy stored in the foam as a function of the applied strain. Based on the simulation results, a simple analytical model was proposed to predict the mechanical behavior of closed-cell foams taking into the effect of the microstructure and of the gas pressure. An example of application of the simulation tool is presented to design foams with an optimum microstructure from the viewpoint of energy absorption for packaging.